During conventional hemofiltration, blood from a patient is generally passed through a hemofilter on one side of a semipermeable membrane. Through this membrane, plasma water from the blood may then be ultrafiltered. At the same time, toxic substances in the blood, such as urea, are removed. For a normal patient, the amount of ultrafiltrate is usually on the order of magnitude of 20 liters, and must therefore be replaced by a replacement of infusate solution which consists of water, to which is added suitable substances for realizing an isotonic solution.
This infusate is normally manufactured centrally in factories, and then transported to the treatment site in cans or large plastic bags containing the sterile isotonic solution. An example of the preparation of such solutions in large quantities is set forth in the article "Successful Production of Sterile Pyrogen-Free Electrolyte Solution by Ultrafiltration", Henderson et al, Kidney International, Vol. 14 (1978), pages 522-525.
In addition, U.S. Pat. No. 4,081,372 to Atkin et al discloses a method for detecting leaks in dialysis systems in which the hemoglobin or hemolysate is used as an indicator for leakage detection in the dialysis membrane interface.